1. Field Of The Invention
This invention generally relates to a method and apparatus for maintaining the patency of an indwelling vein access device and, more particularly, to such a method and apparatus that utilizes a self-energized container to slowly infuse a dilute solution of an anticoagulant drug, such as heparin, into a vein access device and which permits the adding of a medicament without disconnecting the container from the vein access device.
2. Description Of The Prior Art
There are numerous approaches to patency maintenance currently being utilized in venipuncture practice. The most common approaches are the heparin lock procedure and the KVO procedure.
In the KVO procedure a KVO solution (generally a saline solution) is slowly directed through the vein access device (IV catheter) into the patient at a flow rate generally from about 1 ml/hour to about 10 ml/hour. While this procedure seems to maintain the patency of the vein access device, it has the disadvantage of infusing a large volume of fluid into the patient and it limits the mobility of the patient.
In the widely used heparin lock procedure, a concentrated heparin solution is contained in a capped off segment of tubing in fluid communication with the vein access device. The concentration of the heparin is generally from about 10 to about 100 international heparin units per milliliter of diluent. At these concentrations of heparin, it is necessary to initiate a flush procedure of the heparin lock device and vein access device prior to infusion of most antibiotic drugs through the vein access device, in order to avoid contamination resulting from the incompatibility of the drug with the heparin. Most heparin lock devices utilize the cumbersome SASH procedure in which (a) the device is flushed with a bolus dose of saline solution, (b) the medicament or drug is infused into the device, (c) the device is again flushed with a bolus dose of saline solution, and (d) the device is filled with the concentrated solution of heparin. While this procedure is widely regarded as effective to maintain patency of the vein access device, it is generally regarded as being time consuming and costly.
There is a need for a method and apparatus for reliably maintaining the patency of a vein access device in a manner that minimizes manipulative steps, is economical, minimizes the volume of fluid that is infused into the patient, and does not inhibit patient mobility.